The present invention relates to an electrical connection box for automotive vehicles and is particularly designed to highly utilize a wire laying space by inserting a plurality of wires one over another into a wire groove formed in an insulating plate mounted in a casing of the electrical connection box.
Among the electrical connection boxes of this type, there is known the one for easily responding to a design change of the internal circuits, in which box wires are arranged instead of the use of a busbar formed by punching a conductive metal plate, and the connection between the wires and external input/output terminals and the connection between the wires are established by the use of cramping terminals.
The above wires are laid as follows. After being laid in a wiring mold formed with a wire groove having the same pattern as a wiring pattern, the wires are transferred to a casing or an insulating plate on which cramping terminals are already mounted so that the wires are cramped by the cramping terminals at the same time when they are laid.
Instead of the method which employs the wiring mold, the present applicant previously proposed a method for laying wires directly along the wire groove formed in the insulating plate.
When a wire 2 is to be laid along a wire groove formed in a mold or a wire groove 1a formed in an insulating plate 1 as shown in FIG. 7(A), the wire 2 is laid into the groove 1a as shown in FIG. 7(B).
The wire 2 is laid as follows. The wire 2 drawn from a path 3a of a wire laying head 3 which moves in one direction along the upper surface of the insulating plate 1 is laid while being arranged in the wire groove 1a using a natural bend R.
As seen in FIG. 7(B), it is difficult to arrange the wire 2 into the groove 1a at a corner portion 1c of the groove 1a using only the natural bend R. Thus, a recess 1d for allowing the wire 2 to bend is formed in the corner portion 1c. By bending the wire 2 in the recess 1d as shown in FIG. 7(C), the wire 2 can be arranged into the corner portion 1c as shown in FIG. 7(D).
However, since the prior art wire laying method is such that the wire 2 is arranged into the groove 1a using the natural bend R, the wire 2 cannot be deeply inserted into the groove 1a as shown in FIG. 6(A).
Accordingly, even if an attempt is made to insert another wire 2B over a previously inserted wire 2A in order to reduce a space taken up by the laid wires, the wire 2B is likely to come out of the groove 1a because the previous wire 2A is not sufficiently deeply inserted. Thus, a plurality of wires 2A and 2B cannot be securely laid one over another.
If another wire groove 1e for the wire 2B is formed inward of the groove 1a for the wire 2A, the wires 2A and 2B can be laid next to each other in the horizontal direction. However, this leaves a problem due to the larger wire laying space needed.
The GB-A-2 264 885 discloses a method and apparatus according to the preamble of the new independent claims. In particular there is disclosed a method for laying a wire, in which a wire drawn from a wire laying head is inserted into a wire groove formed in a wire laying member, wherein the wire layer is inclined to the wire groove, whereby the wire is naturally bent by its contact with the bottom surface of the wire groove.
"IEEE Trans. on comp., hybrids, & manuf. technology, vol. CHMT-4(1981)June, no.2, pages 224-229" discloses an apparatus and method for bonding a wire to a flat surface using adhesives and a stylus for pressing and engaging the wire with the flat surface via the adhesives. The stylus continuously presses the wire during wiring, in particular on the straight portions of the wiring pattern, and preferably according to the tackless wiring also during the wiring of pattern corners.
It is an object of the present invention to provide wire laying method and apparatus for quickly, safely and deeply inserting a wire into a groove, in particular, for realizing a high utilization of a wire laying space, when a plurality of wires have to be arranged.
This object is accomplished by a method and an apparatus defined in claims 1 and 7, respectively.
Preferred embodiments of the invention are subjects of the subclaims.
Preferably, the wire drawn from the wire laying head is inserted into the wire groove using the natural bend, and is forcibly pressed to the specified depth in the vicinity of the end of this bent portion by the pressing pin.
The wire can be forcibly pressed to the specified depth even in the portions where it is difficult to press the wire only using the natural bend, particularly a corner portion and a linear portion having a narrow width. Further, since the wire extending substantially in the horizontal direction in the vicinity of the bent portion is pressed down by the reciprocatingly movable pressing means, in particular by a pressing pin which moves upward and downward in synchronism with the movement of the wire laying head, the sheath of the wire will not be damaged by the friction between the wire and the pressing pin, and the height of the pressing pin can be easily controlled.
Preferably, the method for laying a wire in an electrical connection box is performed by pressingly inserting a wire drawn from a wire laying head into a wire groove formed in a wire laying member inclined to the wire groove while naturally bending the wire by its contact with the bottom surface of the wire groove, wherein the wire being inserted into the wire groove while being bent is inserted into the wire groove while being forcibly pressed down to a specified depth by a pressing pin movably mounted on the wire laying head in the vertical direction.
Preferably, when a plurality of wires are laid one over another in the wire groove, the height of the pressing pin is controlled in such a manner that the pressing pin is lowered to a predetermined position when the lower wire is laid, while being raised to another predetermined position when the upper wire is laid.
Accordingly, the height of the pressing pin is controlled to control the depth by which the wire is inserted into the wire groove. Thus, the wires can be laid in a highly compact manner by inserting the wires one over another in the wire groove.
Preferably, the wire laying member comprises an insulating plate mounted in a casing of the electrical connection box, and wherein the wire(s) is/are laid while being pressing into the wire groove formed at least in one surface of the insulating plate in conformity with a circuit pattern.
Accordingly, the wire is directly laid in the wire groove formed in the insulating plate. Thus, an operation process can be simplified compared to the prior art method according to which the wire is transferred to the insulating plate or casing after being laid in the wiring mold.
These and other objects, features and advantages of the present invention will become more apparent upon a reading of the following detailed description and accompanying drawings in which:
Elements having the same construction and action as the prior art as shown in FIGS. 5 to 7(D) are identified by the same reference numerals and no detailed description is given thereto.
As shown in FIGS. 1 and 2, a head main body 6 is mounted at the lower part of a wire laying head 5 movably upward and downward. A wire retaining arm 7 facing the upper surface of an insulating plate 1 formed with a wire groove 1a is mounted on the main body 6 movably upward and downward.
The head 5 is provided with guide rollers 8, 8 and a feed roller 9 for guiding and feeding a wire 2, respectively. As indicated by arrows in FIG. 2, the wire 2 is drawn from the retaining arm 7 at a specified speed as the feed roller 9 rotates.
The head main body 6 is stroke-controlled such that it moves upward and downward relative to the head 5 at specified strokes.
The retaining arm 7 is movably guided in the vertical direction by a guide member 6a of the head main body 6, and is biased downward by a spring 10 mounted between a projection 6b of the head main body 6 and an upper end of the retaining arm 7.
While the wire 2 is laid, the lower edge or end of a wire drawing path 7a of the retaining arm 7 is constantly in contact with the upper surface of the insulating plate 1 due to the biasing force of the spring 10.
A pressing pin 11 is inserted at the rear side (downstream side) of the wire drawing path 7a of the retaining arm 7 which is wide in a wire laying direction. The pressing pin 11 is secured on a bracket 12 projecting from the head main body 6.
As shown in FIG. 3, wire 2 inserted from one lateral end of an inlet 7a-1 at the upper end of the path 7a comes out from the other lateral end of an outlet 7a-2 at the lower end of the path 7 so that the wire 2 is inserted into the groove 1a inclined at a specified angle to the groove 1a.
Since the retaining arm 7 is constantly in contact with the upper surface of the insulating plate 1 due to the biasing force of the spring 10 as described above, the pressing pin 11 secured on the head main body 6 via the bracket 12 moves downward in the wire drawing path 7a which is located in a fixed position. On the other hand, when the head main body 6 is moved upward, the pressing pin 11 moves upward in the wire drawing path 7a.
The wire 2 passing through the wire drawing path 7a is drawn inclined between the inlet 7a-1 and the outlet 7a-2, and is inserted into the groove 1a inclined to the groove 1a. The inserted wire 2 comes into contact with the bottom surface of the groove 1a, thereby producing a natural bend R.
The wire 2 is forcibly pressed down by the pressing pin 11 in the vicinity of an end of this natural bend R to be properly positioned.
The height of the pressing pin 11 is controlled by controlling the downward stroke of the head main body 6. For example, in the case where three wires 2A to 2C are pressed one over another into the groove 1a as shown in FIG. 3(B), the stroke of the head main body 6 is first set such that the pressing pin 11 has a stroke S3 for pressing the wire 2A to a bottommost position; secondly such that the pressing pin 11 has a stroke S2 for pressing the wire 2B to a middle position; and finally such that the pressing pin 11 has a stroke S3 for pressing the wire 2C to an uppermost position.
Further, when the head 5 undergoes a change of direction at a corner portion 1c of the groove 1a: from a moving direction A to a moving direction C which is at a right angle to the moving direction A as shown in FIG. 3(C), the pressing pin 11 is positioned at the corner portion 1c and the head 5 is rotated in a direction B about the pressing pin 11 as a center of rotation O.
In order to press the three wires 2A to 2C one over another in the groove 1a of the insulating plate 1 using the above constructed wire laying apparatus, the stroke of the pressing pin 11 is set to the stroke S1 corresponding to the uppermost position and the head 5 is moved in the direction A as shown in FIGS. 3(C) and 4(A) so that the wire 2A drawn from the retaining arm 7 is pressed into the groove 1a using the natural bend R.
At the corner portion 1c, the head 5 is rotated in the direction B about the pressing pin 11 as the center of rotation O as shown in FIG. 4(B). In synchronism with the rotation of the head 5, the pressing pin 11 is lowered to have the stroke S3, and the head 5 is moved further in the direction C.
The portion of the wire 2A linearly laid in the direction A is pressed downward by the lowered pressing pin 11, which further presses the wire 2A to the bottommost position where the wire 2A is in contact with the bottom of the groove 1a so that the wire 2A drawn from the retaining arm 7 can be laid in the corner portion 1c and the linear portion 1b of the groove 1a extending in the direction C.
Similarly, when the wire 2B is to be laid, the head main body 6 is moved upward so that the pressing pin 11 has the stroke S1. In this state, the wire 2B drawn from the retaining arm 7 is pressed into the groove 1a using the natural bend R while the head 5 is moved in the direction A. At the corner portion 1c, the pressing pin 11 is lowered to have the stroke S2 in synchronism with the rotation of the head 5 in the direction B.
Accordingly, the portion of the wire 2B already laid in the direction A is pressed to the middle position, and the wire 2B is laid over the previously laid wire 2A in the bottommost position with the stroke S2 in the corner portion 1c and the linear portion 1b of the groove 1a extending in the direction C.
Finally, when the wire 2C is laid in the uppermost position, the head main body 6 is moved upward so that the pressing pin 11 has the stroke S1. In this state, the wire 2C drawn from the retaining arm 7 is inserted into the groove 1a using the natural bend R while the head 5 is moved in the direction A. The wire 2C is forcibly pressed to the uppermost position at the end of the bent portion by the pressing pin 11.
The wires corresponding to the bottommost, middle and uppermost positions are forcibly pressed to the specified depths in the groove 1a by the pressing pin 11 as described above. Accordingly, the wires 2A to 2C can be securely pressed to the specified depths even in the corner portion 1c and the narrow linear portions 1b where it is difficult to press the wires only using the natural bend R.
Since the respective wires 2A to 2C do not come out of the groove 1a, they can be laid one over another in the groove 1a, thereby highly utilizing the wire laying space.
Further, the wire is basically inserted into the groove using the natural bend, and the substantially horizontally extending wire is pressed downward by the pressing pin. Thus, problems such as a scraped sheath of the wire due to friction between the pressing pin 11 and the wire will not arise.
Although the three wires 2A to 2C are laid one over another in the foregoing embodiment, one, two, four or more wires may be laid one over another.
As is clear from the above description, the wire drawn from the wire laying head is inserted into the wire groove using the natural bend, and is forcibly pressed to a specified depth in the vicinity of the end of the bent portion by the pressing pin. The wire can be forcibly pressed to the specified depth even in the corner portion and the narrow linear portions where it is difficult to press the wires only using the natural bend.
Preferably, the wires are pressed to the specified depths by controlling the distance by which the wires are pressed. Accordingly, the upper-located wire(s) can be pressed into the wire groove in such a manner that they do not come out of the wire groove. Thus, a plurality of wires can be laid one over another, thereby highly utilizing the wire laying space.